Bed bottoms



March 6, 1956 A. FERNROTH BED BOTTOMS 3 Sheets-Sheet 1 Filed March 14, 1952 March 6, 1956 A. 1.. FERNROTH 2,736,907

BED BOTTOMS Filed March 14, 1952 3 Sheets-Sheet 2 IIII III]

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March 6, 1956 FERNROTH 2,736,907

BED BOTTOMS Filed March 14, 1952 3 Sheets-Sheet 3 United States Patent.

BED BOTTOMS Arthur Leonard Fernroth, Stockholm, Sweden Application March 14, 1952, Serial No. 276,584 4 Claims. (Cl. -191 Bed-bottoms are previously known comprising a frame supporting cross-wise and length-wise extending saddle- .girths serving as carrying members. Such bed-bottoms, though rather inexpensively manufactured, show relatively poor elastic properties. Therefore, it has become more and more a practice in recent years to construct bed-bottoms comprising cross-wise and length-wise extending rubbet-straps having transversely extending beads at their ends serving for securing the latter to the bed-bottom frame. The elasticity of the bed-bottom will in'this way be extremely good, but the cost of manufacture will be rather high, partly on account of the difficulty of obtaining a satisfactory attachment of the rubber-straps to the bed-bottom frame and partly due to the fact that the straps will have to be vulcanized in determined lengths. There will be no possibility of increasing the tension in the carrying members when their elasticity decreases.

The present invention maybe considered to reside in a combination of the said two previously known types of bed-bottoms, whereby the elasticity of the bottom will be approximately the same as in the known type of bedbottom comprising exclusively rubber-straps, but the cost of manufacture will be appreciably lower than that of this bed-bottom. In addition, it will be possible when necessary, conveniently to increase the tension of the bed-bottom. More specifically, the mainly characterizing feature of the invention consists in that in the carrying straps there are let in strips of rubber or any similar other elastic material at one or more places intermediate their ends, and in that the carrying straps are interconnected by connecting members extending length-wise of the frame, said connecting members being connected at their ends to the endmembers of the frame by means of resilient elements.

The invention will now be explained in conjunction with the accompanying drawings in which:

Fig. 1 is a plan-view of one end of a bed-bottom according to the invention.

Fig. 2, to a larger scale, shows the center-portion of the carrying member located next to one end of the bed-bottom, and its connection with the end-member of the frame.

Fig. 3 is a vertical section along line IIIIII in Fig. 2.

Fig. 4 is a vertical section along line IVIV in Fig. 1.

Fig. 5 is a plan view similar to that of Fig. l but showing a slightly modified embodiment of the invention.

Fig. 6, to a slightly larger scale, shows a vertical section along line VI--VI in Fig. 5.

Fig. 7 is a plan view similar to that of Fig. 2 but showing a spring-attachment means according to a modified embodiment of the invention.

Referring to the drawings, in the embodiments illustrated the bed-bottom frame 1 is thought to be made of wood. The bars 2 forming the longitudinal members of the frame are provided at their upper edge with a chamfer 3 inclined downwardly and inwardly. The frame is provided with a plurality of cross-wise extending carrying straps 4 the outer ends of which are looped around the "too outside of the bars 2 and are attached to the underside of the latter by means of pins 5. The carrying straps 4 consist of three main parts the two extreme ones of said parts, 6, consisting of saddle-girth and the intermediate part 11 of rubber-strap. The latter is attached to the saddle-girth straps in a manner such as to cause the connection to be easily detachable. I

From Figs. 2 and 3 will be clearly seen in what manner this connection could, to advantage, be arranged. The saddle-girth parts 6 are secured at their inner end to one leg of a closed elongated loop 9 made of metal wire. Through the opening 10 of each loop 9 is threaded one end of a doubled endless strip 11 of rubber. Underneath the loops said strip is located a rod 12 of mainly triangular cross-sectional shape and suitably made of hard wood, said rod 12 being inserted in the doubled end portion of said rubber-strip in such a manner that one of the edges of the rod engages said loop-opening 10 from below. By the pull exerted on the rubber-strip, said rod will be wedged in the opening and will thus be prevented from sliding out end-wise.

The loops 9 of the various carrying straps 4 are interconnected by chain links 13, and the loops 9 of the two carrying straps adjacent to the end-members of the frame are connected to the end-members 15 of the frame by helical springs 14, respectively. The extreme ends of the helical springs 14 project into bores 16, respectively, in the said end-members 15. In the embodiments shown in Figs. 1 to 6, said helical springs 14 are secured to the endmembers 15 by pins 17, respectively. The attached ends of the helical springs 14 are situated at a lower level than that of the unloaded carrying straps 4 (Fig. 4).

in the modified embodiment of the spring attachment illustrated in Fig. 7, each helical spring 14 is connected to the corresponding end-member 15 of the frame by an adjustable screw 17a, which passes through a through-bore 16a in said end-member with freedom for rotation. The head of said screw abuts the outside of said end-member. The screw 17a extends longitudinally of the helical spring and projects into the adjacent open end of the latter and into engagement with a nut 21 or the like which is attached to the spring between two adjacent windings thereof and with its threaded bore in coaxial alignment with said spring 14. By this means it will be possible when necessary to adjust the tension of the several helical springs 14 and thus that of the connecting members 13 of the bedbottom.

When the bed-bottom is being loaded only the rubberstrips 11 will be tensioned initially. Not until the loading has grown so heavy that the depression is approximately that indicated by broken lines 18 in Fig. 4, also the helical springs 14- will be tensioned and thus counteract the depression of the carrying straps 4. This will cause the favorable result that the bed-bottom will be soft when normally loaded but still retain the ability of resisting heavy loads.

The mounting is advantageously carried out in the following way. The rubber-strips 11 are first inserted in oppositely disposed loops 9 which are connected with adjacent loops by links 13. The loops 9 of the two outermost carrying members are then attached to the frame endmembers 15 by means of pins 17, Fig. 2, or alternatively, by means of adjustment screws 17a, and the helical springs 14. Thereafter the saddle-girth parts 6, which have in advance been attached with their inner ends to the corresponding loop-legs 8, are attached to one of the longitudinal frame members 2 and suitably in such a manner as to render to the saddle-girth parts at and near the central portion of the bed-bottom a slightly shorter effective length. When the saddle-girth parts are attached to the opposite longitudinal frame-member the rubber-strips 11 of the carrying straps 4 at and near the central portion of the frame are tensioned somewhat more than the other ones. Then the result will be that the lines (see Fig. 1) along which the loops 9 extend will be curves which are mutually slightly more concave, as seen from one towards the other, at the center of the bed-bottom than at its ends.

- If after some time of use one or more of the rubber strips 11 should tend to be stretched, then they may conveniently be tensioned again in that the respective saddle-girth parts are loosened at the ends and fastened again after having been tensioned. As Will be seen from Fig. 3, replacement of rubber strips will be an easy task.

In the embodiment illustrated in Fig. 5, the chain links 13 serving as connecting members between the loops 9 have been replaced by two parallel saddle-girths 19 which by sewing or in any suitable other manner are attached to the saddle-girth parts 6 of the carrying straps 4. At their ends, the saddle-girth straps 19 are attached by means of a wire loop 20 and the helical springs and pins 17 to the end-members 15 of the frame.

The embodiments illustrated and described are to be considered merely by way of example, the bed-bottom and its several parts being susceptible of various structural changes without departing from the scope of the invention. Elements other than rods 12 may thus be employed for the detachable attachment of the rubber-strips to the saddle-girth parts 6. The helical springs 14 might be replaced by elastic connectors similar to those shown in Figs. 2 and 3. Instead of saddle-girth other high-strength bands of jute, hemp or other suitable textile material might be resorted to. The carrying straps could, to advantage, be sprayed with any suitable artificial resin material so as to form on their upper surface a thin, flexible covering film. The rubber-strips 11 might be produced by cutting a rubber hose transversely into pieces of the suitable width.

What I claim and desire to secure by Letters Patent is:

1. A crosswise and lengthwise extendable elastic bottom for beds or chairs in a frame, comprising a plurality of carrying straps extending under tension between the longitudinal side members of said frame, said carrying straps being composed of inelastic material and strips of yielding material inserted intermediate of the ends of the carrying straps, said yielding strips being inserted by means of closed elongated wire loops provided with detaching means, for said yielding strips, said carrying straps being interconnected by elements extending lengthwise of said frame, said interconnecting elements being attached at their ends to the short end members of said frame by resilient means.

2. An elastic bottom for beds according to claim 1, wherein said elastic strip is endless and is introduced in a double-folded state through the opening of the respective loop from above, and wherein said strip is held below said loop by a rod inserted in the downwardly projecting endportion of said double-folded strip.

3. A crosswise and lengthwise extendable elastic bottom for beds or chairs in a frame, comprising a plurality of carrying straps extending under tension between the longi- ,tudinal side members of said frame, said carrying straps consisting of saddle girths in which exchangeable endless strips of yielding material are inserted intermediate of the ends of said carrying straps; closed elongated wire loops provided in said carrying straps and intended to carry said endless elastic strips introduced in a double folded state from above through the opening of said wire loops; and a rod inserted in the downwardly projecting end portion of said double folded strip.

4. An elastic bottom for beds according to claim 3, wherein said rod is of substantially triangular crosssectional shape having one edge projecting upwardly into engagement with said loop-opening.

References Cited in the file of this patent UNITED STATES PATENTS 127,152 Cooke May 28, 1872 1,068,345 Kemmler July 22, 1913 1,340,510 Weissman et al May 18, 1920 2,318,583 Bernstein May 11, 1943 2,593,831 Bank Apr. 22, 1952 FOREIGN PATENTS 21,349 Great Britain 1891 852,366 France Oct. 23, 1939 

